What we did to start our process is talk about what core values are. We talked about the ideas of core values and how they can be present in every action we do.
One day I was listening to an audiobook on my way to work (something I highly recommend), and I was struck by a very simple idea. The book I was reading was a leadership book that was all about creating and installing culture within a team.
The author said, if you ask your players what the culture of the team is about they should all be able to answer you with similar words. His theory was that if the players do not know, and can not articulate their culture, then how is it supposed to be universal. I was so captivated by the idea that I had to turn off the book and sit and think about the concept for the rest of the drive.